Cool thread!
I've been doing FG, CF, Kevlar(patches, gel coats), and plastic repairs(patches and welding) on Kayaks and canoes for over twenty years. I'll have to go back thru and see what you've been doing.
I'm not sure if you are aware but another great product for sanding foam is Dragon Skin...

I got it from a different source, which I can't remember the name of right off hand but I found that pic here...One piece will last a life time if just used on foam.

You can also make it from a piece of tin, a sharp nail, a hammer, a lot of time...and a lot of beer!

Ever think of working in plaster instead of foam? Those surforms do a great job shaping plaster.

Little air belt sanders work pretty good.

I can see how shaping a rough plaster form may work very nicely. I'll have to keep that in mind. Thanks, PBG!

Quote:

Originally Posted by bwalsh

Cool thread!
I've been doing FG, CF, Kevlar(patches, gel coats), and plastic repairs(patches and welding) on Kayaks and canoes for over twenty years. I'll have to go back thru and see what you've been doing.
I'm not sure if you are aware but another great product for sanding foam is Dragon Skin...

I got it from a different source, which I can't remember the name of right off hand but I found that pic here...One piece will last a life time if just used on foam.

You can also make it from a piece of tin, a sharp nail, a hammer, a lot of time...and a lot of beer!

bwalsh, welcome to the thread! That Dragon Skin looks like some mean stuff. I'm sure it would make quick work of some foam. Do you buy it in sheets and adapt it to your tooling/purpose? I might have to try making my own with your nail and tin technique. Thank you for the ideas!

How did you get into the canoe/kayak repari business?

I do a lot of kayaking with family and friends.I think that it would be a hoot to build a composite kayak someday. Maybe a fancy tandom open water boat made out of carbon, Kevlar, and some nice wood trim. That would be one fancy kayak.

bwalsh, welcome to the thread! That Dragon Skin looks like some mean stuff. I'm sure it would make quick work of some foam. Do you buy it in sheets and adapt it to your tooling/purpose? I might have to try making my own with your nail and tin technique. Thank you for the ideas!

I've only seen it in 4" square(5"?) pieces like in the photo. As long as you are just using it for foam one piece will/should last a lifetime.

How did you get into the canoe/kayak repari business?

I have worked for a Canoe livery/outfitter on the South Fork Shenandoah River in Bentonville Virginia on and off since 1989. I've also paddled whitewater, in FG and plastic boats(canoes but mainly Kayaks) since 1986.

We used to have to build the boats when they were shipped from the factory. We also install skid plates and do some repairs/patches. Just last year I talked the boss into buying a plastic welder. It was just a cheap Harbor freight model but has already paid for itself in repairing our own cracked kayak and Canoe hulls.The FG work I've done was to repair my own glass boats. I've done more repairs to my stuff then to customer boats.

I do a lot of kayaking with family and friends.I think that it would be a hoot to build a composite kayak someday. Maybe a fancy tandom open water boat made out of carbon, Kevlar, and some nice wood trim. That would be one fancy kayak.

I'm friends with a few well known(in the world of whitewater) FG whitewater Kayak boat builders. Here's a website for the only one left who still builds custom Kayaks for a living...

Next, I'll need to do just a little finish sanding/shaping on the foam. Once everything is semi smooth, I'll lay down a couple layers of 8oz glass and epoxy to make a nice durable, hard, sandable surface in which to do the final fairing (finishing) with Bondo followed by a couple coats of Duratech which is a 2k polyester high build primer that can be sanded and polished to a high shine. I want this mold to be grade A with flanges in the 6" range to make it easy to use for infusion.

Anyhow, more to come soon...

Might want to rethink any polyester blend app..... as anything polyester will melt your foam. Even bondo is of a polyester blend. HAAAAALLLTTTTTT...... Even you are putting it on top of epoxy.... If it finds it's way through, a small pinhole, your screwed.

Might want to rethink any polyester blend app..... as anything polyester will melt your foam. Even bondo is of a polyester blend. HAAAAALLLTTTTTT...... Even you are putting it on top of epoxy.... If it finds it's way through, a small pinhole, your screwed.

This is very good advice. However in this scenario I have taken measures to help keep this from happening. Hopefully I have all my basses covered like I think I do.

This is very good advice. However in this scenario I have taken measures to help keep this from happening. Hopefully I have all my basses covered like I think I do.

Good to hear. I did the same once, only to ring that the gases permitted through small pinholes, and deformed the foam..... It was polyester not bondo. As long as you are aware of the incompatability...... Which it sounds like you are..... :)

Looking good. Have you done much work with bondo? Pays dividends to apply as smoothly as possible, and not to add much more than you need. Was making a lot of unnecessary work for myself until I got the hang of that. Also, another thing I started doing was to do some preliminary sanding/shaping before the bondo hardens. There's about a 10 minute window when it's really great to work with. Not so wet that it will smear and ball-up when you sand it, but still soft enough that you can knock down the high spots with ease. Saves a ton of time/effort.

Looking good. Have you done much work with bondo? Pays dividends to apply as smoothly as possible, and not to add much more than you need. Was making a lot of unnecessary work for myself until I got the hang of that. Also, another thing I started doing was to do some preliminary sanding/shaping before the bondo hardens. There's about a 10 minute window when it's really great to work with. Not so wet that it will smear and ball-up when you sand it, but still soft enough that you can knock down the high spots with ease. Saves a ton of time/effort.

I'm no Bondo expert, that's for sure! How long after you apply the Bondo do you want to do your prelim sanding?

Hard to say, but you'll get a feel for it. Try slicing the high ridges off with a razor blade, and see if it cuts through cleanly, without sticking to the blade. Forgot to mention that shaving down those ridges with a razor blade also works really well. Forget the name of it, but there's a long thin cheese-grater-looking tool that makes quick work of shaping soft bondo (not shown). Then I usually switch to course files to even out those compound curves. Concave surfaces are a little more difficult, so shaping and sanding while soft makes all the difference.